#include <iostream>
#include <string>
using namespace std;
class A{
    public:
    A(){
        cout << "This is class A::A()" << endl;
    }
    A(int a,int b){
        cout << "This is class A::A(int a,int b)" << endl;
    }
};
class B:public A{
    public:
    B(int a,int b){//Khong chi? ro~ lap. chong` constructor nao` cua? lop' base thi` se~ goi. ham` constructor default cua? lop base
        cout << "This is class B::(int a,int b)" << endl;
    }
};
class C:public A{
public:
    C(int a,int b):A(a,b){//Chi? ro~ lap. trong` ham` A(int a,int b) cua? lop' base A thi` no' se~ goi. ham` constructor do'
        cout << "This is class C::C(int a,int b)" << endl;
    }
};
/*
int main(){
    B b(5,10);
    C c(5,10);
    cout << endl;
    return 0;
}
**/